In other words, the ligament injury is a result of subtle, slow degeneration that has been taking place over a few months, or even years, rather than the result of sudden trauma to an otherwise healthy ligament. Most commonly, CCLD is caused by a combination of many factors, including aging of the ligament (degeneration), obesity, poor physical condition, conformation, and breed. This “traumatic” rupture can happen in dogs but is quite rare. In humans, trauma (such as skiing, football, or soccer injuries) is the most common reason for injury of the ACL. For athletic patients, surgery in combination with joint supplements is recommended to slow down progression of arthritis and to eliminate/minimize lameness, though many non-surgical treatment options are also available. While the degree of lameness with CCLD varies, it invariably causes arthritis in the long term. Hence, the condition is frequently referred to as “cranial cruciate disease” (CCLD) rather than “cranial cruciate ligament rupture” (CCLR). Furthermore, dogs suffer from different degrees of rupture (partial, complete). The development of this problem in dogs is much more complex than in humans. Rupture of the CCL is one of the most common reasons for hind limb lameness, pain, and subsequent arthritis. It serves many important functions in the joint such as shock absorption, proprioception, and load bearing, and is frequently damaged when the CCL is injured. The meniscus (see Figure 1) is a cartilage-like structure that sits in between the shin and thigh bone. In humans the CCL is called the anterior cruciate ligament (ACL). The cranial cruciate ligament (or CCL, see Figure 1) is one of the most important stabilizers inside the knee (also called “stifle”) joint, the middle joint in the back leg. Cranial cruciate ligament (blue/purple), meniscus (red), caudal cruciate ligament (green).

The insert shows a ruptured cranial cruciate ligament (also note that the shin bone is displaced forward and crushing the meniscus. 1: Illustration of the anatomy of the dog’s knee.

Loose Screws by Karen Templeton